(20S*,24S*)-25-Hy-droxy-20,24-ep-oxy-A-homo-4-oxadammaran-3-one (Chrysura) isolated from the leaves of Walsura chrysogyne

The Genus Walsura: A Rich Resource of Bioactive Limonoids, Triterpenoids, and Other Types of Compounds

Medicinal plants of the genus Walsura (family Meliaceae) are native to tropical zones of a number of Asian countries, and have been used in systems of folk medicine. Several original research articles on Walsura species are available, but an overview highlighting the phytochemical and biological aspects of the compounds isolated to date is so far absent. Since the 1970s, phytochemical investigations on the genus Walsura have been undertaken, and more than 220 compounds from ten species have been identified. Natural products from Walsura species that have received the most attention are limonoids (114 compounds) and triterpenoids (72 compounds). Walsura limonoids have been characterized structurally as having diverse skeletons and more than 100 such compounds are new to the literature, while dammaranes, tirucallanes, and apotirucallanes are the main triterpenoid types from this genus. Other Walsura constituents comprise sesquiterpenoids, flavonoids, sterols, lignans, xanthones, and anthraquinones. Walsura species constituents have also been studied in natural product drug discovery screening programs. Many in vitro biological and some in vivo pharmacological investigations have been carried out on Walsura species isolated compounds. Walsura components display properties such as cancer cell cytotoxicity, antimicrobial, antidiabetes, anti-inflammatory, antioxidant, antifeedant, antifertility, ichthyotoxic, and neuroprotection activities.

Walsogynes H-O from Walsura chrysogyne

Eight new limonoids, walsogynes H–O (1–8) were isolated from the barks of Walsura chrysogyne, and their structures were determined on the basis of the 1D and 2D NMR data. Walsogynes H–M (1–6) and O (8) were concluded to be 11,12-seco limonoids with a dodecahydro-1H-naphtho[1,8-bc:3,4-c′]difuran skeleton, and walsogyne N (7) to be 11,12-seco limonoid sharing a unique dodecahydronaphtho[1,8-bc:5,4-b′c′]difuran skeleton. Walsogynes H–O (1–8) exhibited potent antimalarial activity against Plasmodium falciparum 3D7 strain with IC₅₀ value of 2.5, 2.6, 1.6, 2.5, 1.5, 2.6, 2.1, and 1.1 µM, respectively.

Triterpenoids from Walsura trichostemon

Bioactivity guided separation of Walsura trichostemon stem methanolic extract led to the isolation of four new dammarane (1-4) and two new apotirucallane triterpenoids (5-6), together with one limonoid (7), 11,25-dideacetyltrichostemonate, 12β, 20S, 24R-trihydroxydammar-25-en-3-one and 12β, 20S, 25-trihydroxydammar-23-en-3-one. Compounds 1-7 showed in vitro inhibitory activity on the proliferation of A549, human lung adenocarcinoma cell line.

Apowalsogynes A and B, Two Highly Oxidized 3,4-Seco-Apotirucallane Triterpenoids from Walsura chrysogyne

Two new 3,4- seco-apotirucallane triterpenoids, Apowalsogynes A and B (1 and 2), were isolated from the barks of Walsura chrysogyne, and their structures were determined on the basis of the NMR and CD spectra, and by using the modified Mosher's method. In addition, the cytotoxic activities of 1 and 2 against various cancer cell lines were evaluated.

Plant Resources, (13)C-NMR Spectral Characteristic and Pharmacological Activities of Dammarane-Type Triterpenoids

Dammarane-type triterpenoids (DTT) widely distribute in various medicinal plants. They have generated a great amount of interest in the field of new drug research and development. Generally, DTT are the main bioactive ingredients abundant in Araliaceae plants, such as Panax ginseng, P. japonicas, P. notoginseng, and P. quinquefolium. Aside from Araliaceae, DTT also distribute in other families, including Betulaceae, Cucurbitaceae, Meliaceae, Rhamnaceae, and Scrophulariaceae. Until now, about 136 species belonging to 46 families have been reported to contain DTT. In this article, the genus classifications of plant sources of the botanicals that contain DTT are reviewed, with particular focus on the NMR spectral features and pharmacological activities based on literature reports, which may be benefit for the development of new drugs or food additives.